Primary leiomyosarcoma of bone: report of two cases in extragnathic bones

PRIMARY LEIOMYOSARCOMA OF BONE: CLINICOPATHOLOGIC AND PROGNOSTIC FACTORS ANALYSIS IN A SINGLE INSTITUTION

Objective

Primary leiomyosarcoma of bone (PLB) is a rare type of malignant bone tumor considered as a variant of the spindle cell sarcomas (SCS). The objective of this study was to analyze the clinicopathologic and the prognostic factors of patients with PLB treated at a single institution.

Methods

We retrospectively reviewed the records of 22 patients with pathologically confirmed PLB. The data collected were: age, sex, tumor size and location, grade and stage of the disease and histopathologic features. Mean age was 45.5 years (range, 17 to 73 y). Location was: upper limb (27.3%), lower limb (68.2%) and pelvis (4.5%). Patients had high grade in 90.9% of the reports. Margins were negative in 77.3% of the cases. Histological reports describe spindly sarcomatous cells arranged in fascicles with increased vascular formation without osteoid or chondroid matrix production. On immunohistochemistry, smooth muscle actin and desmin where positive in all cases.

Results

Mean follow-up time was 73.5 months (range, 5.3 to 331.1 m). We found 22.7% of local recurrence (LR). Distant metastasis (DM) was reported in 9 (40.9%) patients. Lung metastasis was the only DM affected site. Overall survival (OS) rate in 5 years was 59.1%. Predictors of OS were LR and DM.

Conclusions

PLB is an extremely rare malignant bone tumor that has a higher rate of DM and similar OS prognosis compared with other bone sarcomas. Level of Evidence IV, Case Series.

Primary leiomyosarcoma of bone--a clinicopathologic study of 8 uncommon cases with immunohistochemical analysis and clinical outcomes

Primary leiomyosarcoma of bone is a rare and a diagnostically challenging tumor entity. Over a 7-year period, we identified 8 such cases that fulfilled the diagnostic criteria in 6 men and 2 women, with age ranging from 25 to 59 years (mean, 42.7 years). All cases were noted in the lower limbs, including femur and tibia as the commonly involved bones in 4 and 3 cases, respectively. On radiography, the most consistent feature was a solitary osteolytic lesion with cortical destruction, unassociated with matrix formation. On histopathology, all cases showed spindly sarcomatous cells, mostly arranged in fascicles and whorls. Of 8 cases, 6 (75%) were of high grade. Prominent vasculature was noted in 5 cases. Two cases displayed focal mineralization, including calcification and heterotropic woven bone formation in 1 case each, but lacked malignant osteoid or chondroid matrix. One case showed osteoclast-like giant cells. On immunohistochemistry, smooth muscle actin was diffusely positive in all cases (100%), desmin was positive in 6 (75%) of 8 cases, and h-caldesmon was positive in 5 (83.3%) of 6 cases. Five cases underwent surgery, including 3 amputations and 2 wide excisions. One case underwent chemotherapy. On follow-up, 5 cases developed metastasis, including 1 case with another, who died within 17 and 5 months. Leiomyosarcoma of bone is uncommon and diagnostically challenging. An index of suspicion is necessary for this diagnosis, especially in cases of lytic, destructive bone lesions, unassociated with matrix production, that show spindly sarcomatous cells on histopathology. Immunohistochemical analysis, including an optimum panel formed by smooth muscle actin (diffuse positivity), desmin, and h-caldesmon, is necessary for substantiating this diagnosis. Surgery forms the treatment mainstay. The prognosis appears to be dismal.

Primary leiomyosarcoma of extragnathic bone: clinicopathologic features and reevaluation of prognosis

CONTEXT

Leiomyosarcoma most commonly involves the female genital tract and occasionally arises within the retroperitoneum, abdominal cavity, or the soft tissues of the extremity. Presentation as a primary bone tumor is extraordinarily uncommon, potentially leading to misdiagnosis. The prognosis is traditionally thought to be dismal. However, this conclusion is largely based on individual case reports and small series, in some of which the pathologic diagnosis is not well documented.

OBJECTIVE

To review the clinicopathologic features of well-established cases of primary skeletal leiomyosarcoma and reevaluate the prognostic implications thereof.

DATA SOURCES

A National Center for Biotechnology Information PubMed search of the English language literature identified 104 authenticated cases of primary leiomyosarcoma of extragnathic bone. An additional 3 cases are reported and illustrated herein.

CONCLUSIONS

Approximately half of all patients with primary skeletal leiomyosarcoma either presented with metastatic disease or developed metastases within 1 year of diagnosis. The 5-year overall and disease-free survival rates were 59% and 41%, respectively, comparable to that of other skeletal sarcomas. As for other bone and soft tissue sarcomas, high histologic grade and tumor stage are predictive of poor outcome.